The Colt M1911A1 is an available pistol in-game. It is rarely used by U.S. Army soldiers in single player but is the most common equipment for U.S. multiplayer classes.
Makarov PM
The Makarov PM is an available pistol in-game. Like the TT-33 and M1911A1, the Makarov is rare in single player, in multiplayer it is used by the "Machine gunner", "Sniper" and "Radioman" classes. Both Soviet and Chinese (Type 59) models are used. It also incorrectly holds 9 rounds.
Smith & Wesson 39
The Smith & Wesson 39 is an available pistol in-game. It is incorrectly equipped with a suppressor, and incorrectly called the "Hush Puppy". In the game it shares the .45ACP ammunition of the M1911A1 instead of the correct 9x19 NATO. It is used by U.S. Special Forces and is the primary pistol used in the Tunnel Rat mission.
Smith & Wesson Model 10
The Smith & Wesson Model 10 is an available revolver in-game. For some reason described in the game as a "Chinese copy of some Colt revolver". It is the main handgun of the Vietcong; particularly prevalent in the tunnel levels, it is quite accurate but slow to reload although a speedloader appears to be used. In multiplayer mode, it is used by the "Medic" class on both teams.
Tokarev TT-33
The Tokarev TT-33 is an available pistol in-game. It is the standard sidearm of the North Vietnamese Army along with the Chinese copy (Type 54). Rare in the single player campaign, in Vietcong: Fist Alpha it is more common. It also is a standard weapon for the "Fighter" and "Sapper" Vietcong classes in multiplayer.
Submachine Guns
M3 "Grease Gun"
The M3 "Grease Gun" is an available submachine gun in-game. Its recoil (in game) drives the muzzle down instead of up. The M3 was rarely issued to US forces (except for armoured vehicle and aircraft crews). However, it was used extensively by the South Vietnamese, especially irregular troops like the Civic Guard. US Marines, and US Army special forces also used it. The M3 is rare in the game. In the single player campaign it is often used by local Vietcong fighters. In multiplayer it can be chosen by US soldiers and the Radioman. The M3 shares the same ammunition as the Thompson.
M1A1 Thompson
The M1A1 Thompson is the U.S.'s main submachine gun, and the first select-fire weapon, widely used by US soldiers in the single player campaign. Its main characteristics are the high firing rate, good stopping power and the short reload time.
Sten Mk IIS
The Sten Mk IIS is a suppressed version of the British World War II Sten submachine gun. It is only available in the Vietcong: Fist Alpha expansion.
Sa. Vz.61 Škorpion
The Sa. Vz.61 Skorpion is an available SMG in-game. It has a high rate of fire and easily controllable in full auto, due to the reaction of the .32 ACP cartridge. It is only available in the Vietcong: Fist Alpha expansion.
Note: the name "Skorpion" or "Scorpion" was created only as after-market term used after the '90 to indicate both the SA 361 machine pistol and the SA 91s civilian pistol.
PPS-43
The PPS-43 is an available SMG in-game. It is common throughout the campaign. It has a curved magazine with a capacity of 35 7.62x25mm Tokarev rounds. In multiplayer is the Vietcong's common primary weapon along with the AK-47. The Chinese copy is designated Type 54.
PPSh-41
The PPSh-41 is an available SMG in-game. It is loaded with a 71 round drum magazine and shares the same ammunition of the PPS-43. Used mainly by the Vietcong, but can sometimes be seen used by NVA officers. The Chinese copy is designated Type 50.
Shotguns
Baikal IZh-43
The Baikal IZh-43 is an available shotgun in-game. It can fire either one, or both shells. Rare in single player, and likely the U.S. counterpart, in multiplayer is used only in close combat or for a "personal challenge" (due its short range, low capacity and the long reload time make it rather difficult to use effectively). It is also anachronistic, since the IZh-43 was put into production only in 1986. The Baikal IZh-58, which is the model the IZh-43 was based on, would be the correct choice for the time period.
Remington 870
The Remington 870 is available in-game. In game it has a 7 round magazine and plastic composite furniture. In the SP Campaign it is often used by the ARVN Soldier Sgt. Le Duy Nhut. In multiplayer is deadly at short range.
Rifles
M1 Carbine
The M1 Carbine is widely used by ARVN soldiers and sometimes by Vietcong fighters, fitted with a detachable bayonet.
Colt XM16E1
The Colt XM16E1 is the standard issue U.S. Army assault rifle, fitted with a detachable M7 knife bayonet. Probably the best and most used weapon in game. In Vietcong the rifle uses 20 round magazines loaded with 18 rounds (loading a magazine with two rounds less than standard capacity is a trick often used by troops to reduce magazine-related malfunctions as well as to prevent accidentally overloading them) and it can be found in the armoury later in the game, the arrival of the "new M16 rifles" is quoted in Hawkins' diary.
M14
The M14 is available only in the Vietcong: Fist Alpha expansion and can also fitted with an ART optical sight. It is used by U.S. Army snipers.
The SKS rifle is a Soviet battle rifle with a non-detachable 10 round magazine that can be reloaded only when empty. The SKS is fitted with an integral under-barrel folding spike bayonet that can be used in the Vietcong: Fist Alpha expansion. Used by Vietcong fighters and North Vietnam Army (NVA) soldiers.
AK-47
The AK-47 is the standard Soviet assault rifle, used by Main Force Viet Cong fighters and NVA soldiers. The version seen in the game is the Type III version with milled receiver, equipped with a detachable AK-47 Type 1 knife bayonet and magazine loaded with only 28 rounds instead of the normal 30 rounds. In the conflict the Vietnamese forces used it alongside the slightly more modern AKM and the Chinese Type 56.
Tokarev SVT-40
Available only in the Fist Alpha expansion pack, also fitted with a PU optical sight and used by Regional Vietcong snipers. Strangely enough it is equipped with a 20 round magazine and has the capability to fire in full automatic mode, more like an AVT-40.
Mosin Nagant 1938 Carbine
Russian and Soviet WW2 military bolt-action rifle, used by Local Vietcong snipers and fighters.
Sniper Rifles
Dragunov SVD
The Dragunov SVD is called the "SVD-63", fitted with a PSO-1 4x optical sight and a detachable AKM Type 1 knife bayonet. Rare to see in Single player, it is usually used by NVA snipers, but it is possible to see it used by an ARVN marksman during the "Hamburger Hill" mission. Great damage, rapid fire capability and high precision make this rifle one of the most deadly weapons of the game. Note that the bayonet becomes useable in Vietcong: Fist Alpha.
M1C Garand
The M1C Garand with a M84 scope is the standard U.S. Army sniper rifle in the original game.
Machine Guns
M60
The M60 is the only U.S. portable Machine Gun. It is heavy and affected by a wild recoil and is the main weapon of Sergeant First Class C.J. Hornster. All the models seen in game have the bipod and front-sight removed. It it also seen as a mounted weapon in some levels.
Degtyarev DP-28
The Degtyaryov DP-28 is only available in "Fist Alpha", with accuracy problems and heavy recoil. Used only by Local Vietcong units, it is later replaced by the Degtyarev RPD.
RPD
The RPD was often used by the VC and NVA; it is more accurate than the M60.
ZB 53 / Vz.37
The ZB-53 / vz. 37 are mounted on tripods. Used by Regional Vietcong in "Fist Alpha".
Browning M2HB
The Browning M2HB can be seen mounted on M151 Jeeps, UH-1 Hueys and in bunkers.
Launchers
M79 grenade launcher
The M79 grenade launcher can be used in-game. It is used to cover the intermediate distance between the hand grenade and light mortar ranges. Useable only in single player and in very few missions.
Grenades/Explosives
C4
C4s can be found in-game.
M18A1 Claymore
The M18A1 Claymore is only used in multiplayer by the "Engineer" or "Sapper" classes. Notably, it is actually depicted as a remote-detonation mine, rather than the proximity detonation most video games use.